Step 5: Inserting Wire Leads into Heat Shrink Sleeve

Step 6: Applying heat to Shrink Sleeve

Once you are comfortable with the position of the Coin / Button battery and Wire Leads in the Heat Shrink Sleeve, it is time to apply some heat to shr...

To power a DIY LED lab project for a group of inexperienced students, I was looking for an inexpensive, clean, and visually attractive solution to attach a Coin / Button battery to a LED circuit.

After trial and error, I found the following method of heat shrinking wire leads onto the Coin / Button battery terminals to be relatively easy and low cost along with conserving space, providing battery short protection, and was visually attractive.

For lack of a better name, I refer to it as a “Heat Shrink Coin & Button Battery Holder”.

Disclaimer: This “Instructable” is provided “As Is” without any express or implied warranty of any kind including warranties of merchantability, noninfringement, or fitness for a particular purpose. The Author of this “Instructable” does not warrant or assume responsibility for the accuracy or completeness of any information, text, graphics, links or other items contained within this “Instructable” post. In no event shall the Author of this “Instructable” be liable for any damages whatsoever (including, without limitation, lost profits, business interruption, lost information, or damaged electronic equipment and circuits) or be liable for any personal harm / pleasure / death whatsoever (including intentional or unintentional, without limitation, cuts, scratch, punctures, bruises, inhalation, swallowing, or insertions) arising out of the use of or inability to use this “Instructable”, even if the Author of this “Instructable” has been advised of the possibility of such damages or personal risks.

In short... Do your own engineering work and analysis of the approach for your specific implementation to determine validity, safety, and assume accountability for the outcome of your engineering assessment; assess and mitigate the risks specific to your scenario and skill level. Use good sense on how, where, and if to use this approach; if you are unsure, do not use it... I would have said common sense, but common sense is definitely not common.

I did attempt other approaches to secure a Coin / Button battery to a LED circuit; however, my results were mixed.

Incorporation of a button battery holder: Due to confined space and the significant cost adder per project kit, I decided that a molded battery holder was not a viable option.

Variety of taping methods (including some illustrated here on instructables): Taping was not giving me the clean look I desired. Nor was the taping method necessarily easy when attempting to position and secure two loose wire leads to the Coin / Button battery terminals as you wrapped tape around it by yourself.

Solder directly onto the battery terminals: Soldering to the battery yielded limited success and I was concerned with my student’s ability to utilize this method along with any potential battery damage due to excessive heat. I did evaluate batteries with soldering tabs; however, I found them to be a significant cost adder compared to a regular bulk Coin / Button battery.

Conductive glue / epoxy: Yielded similar frustrations as taping and came with the additional concerns around the chemical makeup.

Saw feedback for that carbon glue where the writer used it to solder on solar cell tabs. whilst the convenience of connecting to delicate solar cell tabs might make it an attractive proposition, I wonder whether the reduced efficiency due to the extra resistance would mean an alternative might be worth considering. Your instructable is very nicely executed. I pondered the possibility of using silver paint (expensive I know), using hot glue to give mechanical strength. Still, solder does 99% of jobs and your solution to the battery leads on button cells is a pretty clean and elegant way of taking care of those situations where solder isn't viable.

Thinkgeek.com has a wire glue that might be worth looking at as well. I understand your reluctance to exposing the kids to chemicals. Neither Thinkgeek nor the manufacture's web site shows anything other than some guy in ND using it on his kid's science fair project.

Beyond the potential chemical concerns, the decision not to use Wire Glue (Conductive Glue) for this project was also based on various peer reviews that the Wire Glue had limited tackiness / adhesive qualities on initial application, required components to be held in position or clamped for a long time during drying, and needed to be put on fairly thick to be effective causing concerns around visual appearance. On top of that, I did not think my students had the patients or application precision to effectively use it for this project.

The same stuff that is sold on ThinkGeek is also sold on Amazon, which has several reviews on the product (both positive and negative). http://www.amazon.com/Electrically-Conductive-Wire-Glue-Bonds/dp/B000Z9H7ZW/ref=cm_cr_pr_product_top

It is fairly robust from slippage and tolerates general handling well. However, as you advised, proper positioning on the negative terminal is important and you are going to want to avoid âyankingâ on it.

As noted in the instructable, for added security, a small zip / cable tie can be optionally used to apply additional compression to the heat shrink sleeve, wire leads, and Coin / Button battery package if you feel a particular application needs that additional support.

Most Lithium Coin / Button batteries have a high “operating” temperature (or maximum sustained temperature during operation) of 60 °C. Polyolefin tubing shrinks quickly at about 90 °C and takes a fraction of a second.

Short exposure with the minimum required heat to shrink the Polyolefin tubing followed by a ramped cool down is recommended. A sustained high temperature, above operating max thresholds, can cause self-discharging, battery failure, leakage, or catastrophic failure. So, don’t leave a sustained heat on it.

However, with any engineering activity… I do recommend that you do your own analysis, risks assessment, and draw your own conclusion based on your data.

In any case, i think the heat is far below from what the battery would have suffered if you soldered the leads (as I have done when I needed to put one of these batteries into a GPS to keep memory alive... before heat shrinking).

So thank you very much for your idea, another good example of the advantages of KISS (Why solder? Heat shrink is enough!)

More of an observation of how things have changed in a generation - your instructable is very well thought and laid out, the effort taken is clearly seen. Well done!

I have some old books & magazines belonging to my dad that for all intents & purposes were the "Instructables" of the time.

The first thing that struck me was the difference in 'instructing' & the projects proposed, you were expected to 'make do', improvise & understand what you were letting yourself in for.

The projects proposed were (by today's standards) 'adventurous' - if you could not obtain a specific item ...use something close - you were given enough info to get going & expected to continue in your own way - once started if things went wrong well ....you should have known better than to start.

In short I could not smile inwardly when reading your instructable & its comprehensive detail - as in the back of my mind I kept on thinking that the 'old instructable' would have began & ended with the original picture ....but in black & white.